Omniverse USD Plugin Fatal Error when loading URDF with urdf-importer

Omniverse Isaac Sim
1

Hi,
I try to load the urdf-File of the turtlebot3_manipulation. Importing the “turtlebot3_manipulation_robot.urdf” via the urdf-importer results in the below Error when pressing on “Import Robot To Stage”, resulting in Isaac Sim crashing:

2021-12-10 13:00:20 [3,751,487ms] [Warning] [omni.isaac.urdf] The path is not a valid usd path, modifying to a_ turtlebot3_manipulation_robot.urdf /home/robolab/ros/catkin_ws/src/turtlebot3_manipulation/turtlebot3_manipulation_description/urdf 2021-12-10 13:05:18 [4,049,416ms] [Warning] [omni.isaac.urdf] Failed to resolve mesh 'package://turtlebot3_description/meshes/bases/waffle_pi_base_for_open_manipulator.stl' 2021-12-10 13:05:18 [4,049,417ms] [Error] [omni.client.plugin] Main: usd_plugin: Used null prim 2021-12-10 13:05:18 [4,049,417ms] [Error] [omni.client.plugin] Main: usd_plugin: Fatal error in void pxrInternal_v0_20__pxrReserved__::Usd_IssueFatalPrimAccessError(const pxrInternal_v0_20__pxrReserved__::Usd_PrimData*)

The xacro-File (turtlebot3_manipulation_robot.urdf.xacro) of the loaded urdf looks like this:

<?xml version="1.0"?>
<robot name="turtlebot3_manipulation" xmlns:xacro="http://ros.org/wiki/xacro">

  <!-- Include TurtleBot3 Waffle URDF -->
  <xacro:include filename="$(find turtlebot3_description)/urdf/turtlebot3_waffle_pi_for_open_manipulator.urdf.xacro"/>

  <!-- Include OpenMANIPULATOR URDF -->
  <xacro:include filename="$(find turtlebot3_manipulation_description)/urdf/open_manipulator_x.urdf.xacro"/>

  <!-- Base fixed joint -->
  <joint name="base_fixed" type="fixed">
    <origin xyz="-0.092 0.0 0.091" rpy="0 0 0"/>
    <parent link="base_link"/>
    <child link="link1"/>
  </joint>

</robot>

The two urdf-Files (turtlebot3_waffle_pi_for_open_manipulator.urdf and open_manipulator_x.urdf) which are included by the above xacro-File can be loaded separately into Isaac Sim via the urdf-importer without a problem. Not sure what’s the problem.

For conversion of xacro to urdf I simply used the command:

rosrun xacro xacro foo.urdf.xacro > foo.urdf

Is it possible to link the two separate parts of the robot inside Isaac Sim as a workaround?

Additional information about the system:

  • Ubuntu 18.04.6 LTS
  • Isaac Sim 2021.1.1-beta.9
  • ROS 1.14.12 melodic

Thanks for your help!

2

before starting isaac-sim, can you set your ROS_PACKAGE_PATH to a location that contains the turtlebot3_description package?
something like:
export ROS_PACKAGE_PATH="/opt/ros/melodic/share"

and then load isaac-sim.sh in the same terminal and try importing again

3

Thanks Hammad_M for your fast response!

I tried export ROS_PACKAGE_PATH="/home/robolab/ros/catkin_ws/src/turtlebot3" but got the same Error message.

For now I have a workaround by replacing all <mesh filename="package://turtlebot3_description/meshes/bases/waffle_pi_base_for_open_manipulator.stl" [...]\> like dependencies, inside the two loaded xacro-files (turtlebot3 and open manipulator), with absolute paths.

1 Like
4

Sounds good!

One last thing, could you run isaac-sim.sh -v and paste any logging output from the URDF importer that gets printed out, i’m curious if its at least trying to look in the right spots for the package"

5

that’s the verbose output message after “Check successful” (I’m also adding a ground plane before loading the robot urdf):

2021-12-21 11:47:17 [173,908ms] [Info] [omni.usd] ResyncedPaths: /World/GroundPlane
2021-12-21 11:47:17 [173,912ms] [Info] [omni.usd] ResyncedPaths: /World/GroundPlane/CollisionMesh
2021-12-21 11:47:17 [173,916ms] [Info] [omni.usd] ResyncedPaths: /World/GroundPlane/CollisionPlane
2021-12-21 11:47:17 [173,917ms] [Info] [omni.usd] ResyncedPaths: /World/GroundPlane/CollisionPlane
2021-12-21 11:47:17 [173,993ms] [Info] [carb.python] Handle changed 3 prims for layer anon:0x12104f80:World0.usd.
2021-12-21 11:47:17 [173,993ms] [Info] [carb.python] Load prim spec tree rooted from /World/GroundPlane
2021-12-21 11:47:17 [173,993ms] [Info] [carb.python] Handle changed prims for layer anon:0x12104f80:World0.usd done.
2021-12-21 11:47:17 [174,052ms] [Info] [carb.settings.python] ISettings.get(...) was called on element that has no value (from python). Use set_default(...) before to set default value. (path = 'ext/omni.kit.widget.stage/exclusion/types')
2021-12-21 11:47:17 [174,052ms] [Info] [carb.settings.python] ISettings.get(...) was called on element that has no value (from python). Use set_default(...) before to set default value. (path = 'ext/omni.kit.widget.stage/exclusion/types')
2021-12-21 11:47:17 [174,052ms] [Info] [carb.settings.python] ISettings.get(...) was called on element that has no value (from python). Use set_default(...) before to set default value. (path = 'ext/omni.kit.widget.stage/exclusion/types')
2021-12-21 11:47:17 [174,052ms] [Info] [carb.settings.python] ISettings.get(...) was called on element that has no value (from python). Use set_default(...) before to set default value. (path = 'ext/omni.kit.widget.stage/exclusion/types')
turtlebot3_manipulation_robot.urdf /home/robolab/ros/catkin_ws/src/turtlebot3_manipulation/turtlebot3_manipulation_description/urdf2021-12-21 11:47:30 [187,249ms] [Info] [carb.python] [py stdout]: turtlebot3_manipulation_robot.urdf /home/robolab/ros/catkin_ws/src/turtlebot3_manipulation/turtlebot3_manipulation_description/urdf


2021-12-21 11:47:30 [187,249ms] [Info] [omni.isaac.urdf] Trying to import /home/robolab/ros/catkin_ws/src/turtlebot3_manipulation/turtlebot3_manipulation_description/urdf/turtlebot3_manipulation_robot.urdf
2021-12-21 11:47:30 [187,249ms] [Info] [omni.isaac.urdf] Loading URDF at '/home/robolab/ros/catkin_ws/src/turtlebot3_manipulation/turtlebot3_manipulation_description/urdf/turtlebot3_manipulation_robot.urdf'
2021-12-21 11:47:39 [196,152ms] [Info] [omni.isaac.urdf] Trying to import /home/robolab/ros/catkin_ws/src/turtlebot3_manipulation/turtlebot3_manipulation_description/urdf/turtlebot3_manipulation_robot.urdf
2021-12-21 11:47:39 [196,152ms] [Info] [omni.isaac.urdf] Loading URDF at '/home/robolab/ros/catkin_ws/src/turtlebot3_manipulation/turtlebot3_manipulation_description/urdf/turtlebot3_manipulation_robot.urdf'
2021-12-21 11:47:39 [196,154ms] [Info] [omni.usd] ResyncedPaths: /physicsScene
2021-12-21 11:47:39 [196,156ms] [Info] [omni.usd] ResyncedPaths: /physicsScene
2021-12-21 11:47:39 [196,161ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation
2021-12-21 11:47:39 [196,162ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation
2021-12-21 11:47:39 [196,162ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation
2021-12-21 11:47:39 [196,164ms] [Info] [omni.usd] ResyncedPaths: /World
2021-12-21 11:47:39 [196,164ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation
2021-12-21 11:47:39 [196,164ms] [Info] [omni.isaac.urdf] Found base link called base_footprint 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link base_footprint has child base_link 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link base_link has child link1 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link base_link has child camera_link 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link base_link has child caster_back_left_link 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link base_link has child caster_back_right_link 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link base_link has child imu_link 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link base_link has child base_scan 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link base_link has child wheel_left_link 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link base_link has child wheel_right_link 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link link1 has child link2 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link link2 has child link3 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link link3 has child link4 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link link4 has child link5 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link link5 has child end_effector_link 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link link5 has child gripper_link 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link link5 has child gripper_link_sub 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link camera_link has child camera_depth_frame 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link camera_link has child camera_rgb_frame 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link camera_depth_frame has child camera_depth_optical_frame 

2021-12-21 11:47:39 [196,165ms] [Info] [omni.isaac.urdf] Link camera_rgb_frame has child camera_rgb_optical_frame 

2021-12-21 11:47:39 [196,166ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks
2021-12-21 11:47:39 [196,166ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_black
2021-12-21 11:47:39 [196,167ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_black/Shader
2021-12-21 11:47:39 [196,170ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_blue
2021-12-21 11:47:39 [196,171ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_blue/Shader
2021-12-21 11:47:39 [196,174ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_brown
2021-12-21 11:47:39 [196,175ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_brown/Shader
2021-12-21 11:47:39 [196,178ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_dark
2021-12-21 11:47:39 [196,179ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_dark/Shader
2021-12-21 11:47:39 [196,182ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_green
2021-12-21 11:47:39 [196,183ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_green/Shader
2021-12-21 11:47:39 [196,186ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_grey
2021-12-21 11:47:39 [196,187ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_grey/Shader
2021-12-21 11:47:39 [196,190ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_light_black
2021-12-21 11:47:39 [196,191ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_light_black/Shader
2021-12-21 11:47:39 [196,194ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_orange
2021-12-21 11:47:39 [196,195ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_orange/Shader
2021-12-21 11:47:39 [196,198ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_red
2021-12-21 11:47:39 [196,199ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_red/Shader
2021-12-21 11:47:39 [196,202ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_white
2021-12-21 11:47:39 [196,203ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/Looks/material_white/Shader
2021-12-21 11:47:39 [196,205ms] [Info] [omni.isaac.urdf] Add Rigid Body: base_footprint
2021-12-21 11:47:39 [196,206ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/base_footprint
2021-12-21 11:47:39 [196,209ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/base_footprint
2021-12-21 11:47:39 [196,210ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/base_footprint
2021-12-21 11:47:39 [196,210ms] [Info] [omni.isaac.urdf] Add Rigid Body: base_link
2021-12-21 11:47:39 [196,210ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/base_link
2021-12-21 11:47:39 [196,213ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/base_link
2021-12-21 11:47:39 [196,214ms] [Info] [omni.usd] ResyncedPaths: /turtlebot3_manipulation/base_link
2021-12-21 11:47:39 [196,216ms] [Info] [omni.isaac.urdf] trying '/home/robolab/ros/catkin_ws/src/turtlebot3_manipulation/turtlebot3_manipulation_description/urdf/turtlebot3_description/meshes/bases/waffle_base_for_open_manipulator.stl' (0)

2021-12-21 11:47:39 [196,216ms] [Info] [omni.isaac.urdf] trying '/home/robolab/ros/catkin_ws/src/turtlebot3_manipulation/turtlebot3_manipulation_description/turtlebot3_description/meshes/bases/waffle_base_for_open_manipulator.stl' (0)

2021-12-21 11:47:39 [196,216ms] [Info] [omni.isaac.urdf] trying '/home/robolab/ros/catkin_ws/src/turtlebot3_manipulation/turtlebot3_description/meshes/bases/waffle_base_for_open_manipulator.stl' (0)

2021-12-21 11:47:39 [196,216ms] [Info] [omni.isaac.urdf] trying '/home/robolab/ros/catkin_ws/src/turtlebot3_description/meshes/bases/waffle_base_for_open_manipulator.stl' (0)

2021-12-21 11:47:39 [196,216ms] [Info] [omni.isaac.urdf] trying '/home/robolab/ros/catkin_ws/turtlebot3_description/meshes/bases/waffle_base_for_open_manipulator.stl' (0)

2021-12-21 11:47:39 [196,216ms] [Info] [omni.isaac.urdf] trying '/home/robolab/ros/turtlebot3_description/meshes/bases/waffle_base_for_open_manipulator.stl' (0)

2021-12-21 11:47:39 [196,216ms] [Info] [omni.isaac.urdf] trying '/home/robolab/turtlebot3_description/meshes/bases/waffle_base_for_open_manipulator.stl' (0)

2021-12-21 11:47:39 [196,216ms] [Info] [omni.isaac.urdf] trying '/home/turtlebot3_description/meshes/bases/waffle_base_for_open_manipulator.stl' (0)

2021-12-21 11:47:39 [196,216ms] [Warning] [omni.isaac.urdf] Failed to resolve mesh 'package://turtlebot3_description/meshes/bases/waffle_base_for_open_manipulator.stl'
2021-12-21 11:47:39 [196,216ms] [Error] [omni.client.plugin]  Main: usd_plugin: Used null prim
2021-12-21 11:47:39 [196,216ms] [Error] [omni.client.plugin]  Main: usd_plugin: Fatal error in void pxrInternal_v0_20__pxrReserved__::Usd_IssueFatalPrimAccessError(const pxrInternal_v0_20__pxrReserved__::Usd_PrimData*)

the right path would be /home/robolab/ros/catkin_ws/src/turtlebot3/turtlebot3_description/meshes/bases/waffle_base_for_open_manipulator.stl. The problem might be that the robot definition is inside another package than the robot manipulator urdf loaded into isaac sim.
Reminder: the urdf loaded into isaac sim is at /home/robolab/ros/catkin_ws/src/turtlebot3_manipulation/turtlebot3_manipulation_description/urdf/turtlebot3_manipulation_robot.urdf

6

Are you using isaac sim 2021.2.0 or 2021.2.1? ROS_PACKAGE_PATH support added recently.

Was this with ROS_PACKAGE_PATH set to /home/robolab/ros/catkin_ws/src/turtlebot3/ before you started ./isaac-sim.sh?

It should print out something like Testing ROS Package path ... if it finds the env var was set.

The env var should be set in the same terminal that isaac-sim is started in.
If you did set it in the terminal before starting isaac-sim, then I’ll file a bug and we will look into it

7

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